Tuesday, August 23, 2011

Danger zone: A parasite that turns rats into zombies and manipulates them into losing their fear of cats has been uncovered by scientists

A parasite that turns rats into zombies and manipulates them into losing their fear of cats has been uncovered by scientists.

Cat urine normally acts as natural deterrent to rodents, who are keen to keep their distance from their natural predators.

But researchers found that Toxoplasma-infected male rats exposed to cat urine suffered an increased activation in the brain regions involved in sexual attraction.
At the same time, the brain regions that govern fear were paralysed, as expected.

Co-study author Robert Sapolsky, a professor of neuroscience at Stanford University, said: 'Normally, we would expect Toxoplasma to knock out the normal fear function in the brain, but in these rats the parasite also tapped into the sexual arousal pathway, which is strange.'

Toxoplasma requires the cat digestive system for sexual reproduction.

By not only reducing a rat's fear of the smell around cats, but also attracting them to it, the parasite makes the rodent far more susceptible to being killed by a cat.